This invention relates to the automated filling of orders for goods, and more particularly to the filling of orders requiring a mix of individual items which can be characterized as either high demand or low demand items, i.e., where some items are ordered frequently and other items are ordered less frequently.
Traditional catalog telephone and mail order sales, and now so-called xe2x80x9ce-commercexe2x80x9d sales over the Internet, require retailers to pick ordered items from inventory and accumulate those items into a receptacle or defined location for packaging and shipping to the customer. The simplest, and probably the earliest, system for picking items requires a person, usually referred to as an order picker, to physically search through inventory stored in a warehouse, guided by a list of items required to fill an order. The order picker is required to locate and transfer ordered items to a receptacle or a defined accumulation area where picked items are collected, matched to a specific order, and packed and prepared for shipping to the customer. The cost of such a system is high because it relies heavily on manual labor, and is subject to inefficiencies due to inevitable human error in picking and assembling items to fill an order.
To assist the order picker, and to help track inventory, item identification systems called xe2x80x9cpick to lightxe2x80x9d systems were developed, in which a controller received information identifying items to be picked to fill an order and sequentially or simultaneously activated lights at locations containing items to be picked to fill the order. Guided by the lights, the order picker would move from location to location, remove the required items from the illuminated locations, manually indicate the removal of the items, such as by pressing a switch (which would usually also turn off the light), and then place the items into a receptacle assigned to receive items to fill the order. A benefit of this system was the integration of an inventory tracking system, which allowed inventory records to be decremented each time the order picker pressed the switch or otherwise indicated that an ordered item had been removed from inventory. Such systems nevertheless are limited by their reliance on human order pickers, and are prone to error and fraud.
To improve efficiencies and reduce errors, dedicated dispensers for dispensing individual items were developed. Such a dispenser is disclosed in U.S. Pat. No. 5,271,703, assigned to the same assignee as the present invention. That patent describes a dispenser which uses a plurality of magazines, each stocked with items offered for sale. Items required to fill a purchase order are selectably dispensed from individual magazines into a dynamically assigned order space on a conveyor belt, which accumulates in the order space those items necessary to fill an order. Once all required items are dispensed into the dynamically assigned space on the conveyor belt, the belt moves the items to a second conveyor, which moves the items in a group to a packing station. Variations of that dispenser-based system dispense items directly into passing receptacles or shipping containers, instead of into a defined space on a moving belt.
The use of individual dispensers of inventoried items, such as described in U.S. Pat. No. 5,271,703, clearly requires a dedicated dispensing machine for each item to be dispensed. For some items, the low frequency with which the item is requested by purchasers does not justify the cost of a dedicated dispensing machine. To avoid the cost of dispensing machines for slow selling items, those items were previously picked manually and placed in a receptacle, and then the receptacle was sent to the dispensing machinery where frequently ordered items were automatically dispensed into the receptacles. Such hybrid manual and automated systems reduced, but did not entirely eliminate, the disadvantages inherent in manual order picking.
Moreover, all prior order picking systems, whether manual only or both manual and automatic, need to be replenished when the supply of ordered items runs low or is exhausted. Until now, replenishment was done manually. That is, an individual was required to bring items to their assigned locations within inventory and load the items one at a time into dispensing magazines (or at least replace an empty magazine with a full one) or place the items into a storage bin. The manual replenishment process, like the picking process, is inherently inefficient and prone to errors.
There remains a need for a fully automated order picking system which is able to dispense both high volume (i.e., frequently ordered) and low volume (i.e., infrequently ordered) items with minimal reliance on manual labor in both picking and replenishment of items. The present invention fills that need.
In one of its aspects, the invention encompasses a method of automatically picking items to fill a purchase order. A purchase order is received and information about the identity and quantity of items ordered in the purchase order is extracted from it. A pick list is created from the extracted information a pick list, and the pick list is associated with a receptacle for receiving picked items. A determination is made whether ordered items are of a first type or a second type. If no item of the second type is ordered, the receptacle is directed to a first location where items of the first type are stored and ordered items stored at the first location are automatically picked and placed in the receptacle. If at least one item of the second type is ordered, the receptacle is first directed to a second location where items of the second type are stored. Items stored at the second location re automatically picked and placed in the receptacle and, if at least one item of the first type is also ordered, the receptacle is next directed to a first location where items of the first type are stored. Ordered items stored at the first location are then automatically picked and placed in the receptacle and the receptacle is directed to a location for further processing. If no item of the first type is also ordered, the receptacle is directed to a location for further processing after items stored at the second location have been picked and placed in the receptacle.
In another of its aspects, the invention is a system for automatically picking items to fill a purchase order, and comprises at least one receptacle for receiving items ordered in the purchase order, the receptacle having associated with it unique identifying information; a conveyor for moving the receptacle along a preselected path; a detector along the path for detecting the unique identifying information associated with the receptacle and generating an output signal representative of that information; a system controller which (a) receives the detector output signal and information about the identity and quantity of items ordered in the purchase order, (b) correlates the unique identifying information with the information about the identity and quantity of items ordered in the purchase order, and (c) generates commands; a first location along a first portion of the path of the conveyor for storing items of a first type; a second location along a second portion of the path of the conveyor for storing items of a second type; a director responsive to a command from the controller to direct a receptacle onto the second portion of the path when items of the second type are ordered in the purchase order; at least one picking robot at the second storage location responsive to a command from the controller to pick items of the second type ordered in the purchase order and place the items in the receptacle; and at least one dispenser at the first storage location responsive to a command from the controller to dispense items of the first type ordered in the purchase order into the receptacle.